Amazon .in - Package received without phone

I ordered Oneplus *T with order No. ***-*******-******* ( OnePlus *T-Glacier Blue, *GB RAM, Fluid AMOLED Display, ***GB Storage, ****mAH Battery) from Amazon India on **th October ****.
I purchased the product by using Bajaj Finance EMI Card which is already approved.

The delivery agent details are as below :-
Rocket Kommerce LLP
Haryana

Amazon seller Services Pvt. Ltd.
Unit No. *, Khewat/ khata No. ***/*** Mustatil No. **, village Taoru , Tehsil Taoru, District Mewat, On Bilaspur Taoru Road, Mewat, Haryana

I received the product on **th Oct. ****, upon unboxing the product, the outer amazon packing seemed untempered which we opened but to our surprise, the lamination was precisely cut in a shape that of the rectangular box, I received only a usual manual, adaptor, cable and back cover, there was no phone inside the box. On checking the outer cover it was observed that very smartly the edge of the pack was opened and resealed, one will never know until he sees with an eagle eye. It was tampered.

I have already approached amazon on the customer service number, I have been asked to wait for another * days and that they will investigate the matter and we will have to follow it up on *th of November ****.

However, I also tried to return the product with the option they are giving that is missing accessories but it doesn't not go any further, which means I cannot return it. My Bajaj finance first EMI date is *nd December ****, they have requested me to send them the cancellation communication made to amazon and it's confirmation, to cancel the loan process.
I am unable to return or cancel it from the application, total dependent on the follow up which will happen on *th of November ****.